Well guys looks like I will be building my 2nd Z engine this fall/winter...

First the back story:
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As most of you know I do all of my own work with the exception of my tuning, which I trust to Sharif @ Forged. I blew my stock engine last summer by snapping a rod in half at the small end running the car hard (100+mph for over 10min followed by a top speed run to 160). After several months of consulting with our Z33 experts, I decided to build the following engine.

-Cosworth 96mm 8.8:1 CR pistons
-Eagle Rods
-Cosworth complete engine bearing set
-RevUp oil pump
-ARP mains and L19 head studs
-Cosworth Heads
-JWT C2 cams
-OEM Nissan engine gasket set (including head gaskets)
-And many other parts not inside this engine...

The car made amazing power on Forged Performance's dyno, making 643whp on pump gas/methanol at 18.5psi of boost at redline. This engine made over 75 pulls on the dyno and never had any issues until the very end of this summer when I stopped by on my way home from NOPI to test a larger throttle body and the turbos were not holding boost like they used to, down to 16.5psi at redline. Which I had noticed that over the course of the summer the car was not making the boost it used to and was smoking on deceleration after a hard pull to redline with the car. I had planned on doing the SGP 20G upgrade since the turbos had about 30,000 miles on them and was probably due for a refresh.
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Well, plans changed last Friday night (9/28/07)... I was out cruzing the mean streets of Indianapolis and decided to give a ride to fellow my350Z member Blackbird CPV35. We hoped on the interstate and did a 3rd-4th gear pull, car felt pretty good! Pulled off the exit and made a u-turn back on the interstate, as we were merging off of the on ramp I punched it again in 3rd gear. When the car hit about 5500-6000rpm it stopped pulling hard for a second. When I looked over at my gauges to see what was going on next thing I know coolant spayed all over the windshield!! Needless to say I knew that was not a good thing, we limped the car back off the interstate (with a lot of white smoke) about a mile and pulled into a parking lot. Temps never got over 200 deg and oil psi was normal. Car just felt like it was running on 5 cyl.

From what happened I thought that I had just blown a head gasket and that was it. Car still started right up and ran fine, just a loud pumping noise coming from under the intake manifold and was running on 5 cyl. Called a tow truck and got it back to my place.

Next morning, I started to look at what happened... Noticed that the lower radiator hose was blown off of the motor at the thermostat housing and that the sides of my AMS radiator had ballooned outward a little bit. Something with a lot of pressure caused this to happen! But still figured it was a head gasket, and I was going to replace the turbos anyway so I was going to pull the engine, no big deal right? WRONG!!!

Pulled the intake manifold off and found this...





I have never seen this happen before in the years that I have been involved with cars. But I did know that this was bad news for me! So I pulled the engine out and noticed while I was doing this that the hose coupler on the passenger side turbo, right next to the exhaust manifold, had burst open. This may explain why the car fell on its face right before it self destructed... I also checked the methanol system and it was working properly with no clogs in the nozzle. Once I got everything apart this is is what I found...











The jury is still out as to what exactly happened, but there are a lot of good theories that I have heard... Some think that a steam pocket developed in the cooling system and caused a hot spot on the cyl wall causing a failure. Some think that the methanol kit malfunctioned. Some say the boost leak caused by the coupler bursting caused the FCon freak out for a second being under load and boost then all the sudden it was not. And some think that the stock cyl liner just gave out or the block just had a weak spot in it that finally let go due to fatigue. I tend to think it was probably a combination of a few of these factors that lead to the demise of my engine. I was having to add about a 1/8-1/4 cup of coolant every couple weeks to the engine, found a "sweat" leak from a thottle body heater hose when tearing it down.

Not sure what I am going to do at this point... I did not plan on investing a whole lot more money into the engine at this point, but now I am faced with sleeving this engine, repairing the cyl with an OEM liner or starting over with a fresh core. I do know that I need a new Cosworth piston, rings, and a gasket set at this point. Absolutely everything else checked out fine in the engine. I need to have the head welded to repair the damage there, but that is minor and an easy fix. Once I get the plan figured out I will keep you guys posted as to what I plan to do, or if I get a more definitive answer as to what happened to the engine.



In the mean time I will be working on Louie's car (eagletangogreen) in order to get some money around to fix my own. I was approached by Louie to do some minor work to his car while he was gone overseas and the timing just happened to work out that I need the cash to get mine back on the road. I take a lot of pride in the work that I do on my personal vehicles and I am extremely flattered that I have the opportunity to work on an already amazing car built and tuned by one of the most respected Z shops in the country. I used to own my own shop back in the day and still do a little work on the side to supplement my own hobby. I just do this for friends and local guys to fund my own projects and because I love to wrench on cars! It is just as fun for me to build them, as it is to drive them. I have no plans to open my own shop again and I still work closely with Forged Performance for most of my parts and tuning requirements (including tuning of some other cars I have built for locals). I respect everything that the shop owners are doing on these boards, especially since I have been in their shoes before...

So if any of you guys would like to add what you think may have happened, I am all ears! I learn a lot from these types of forums and would like to hear your opinions as long as they are intelligent.

 

I'm not as smart as you when it comes to cars but it must at least feel good knowing that you have the means to fix something like this on your own. Good luck to you and I hope you get your Z back up and running soon.

 

that looks wierd, it looks like the metal melted!

 

Nooo! Your #'s on METH were insane, Im sorry to see this Joe. Your one of the highest whp (and on the heartbreaker) Z's running around with stock sleeves. You may have just pushed the stock block to its limits? BTW-Im surprised your running the same pistons again, while they likely werent the cause of the failure, you gotta have doubts, no? This sucks right now but you have all fall/winter to figure out your game plan for the next one.

BTW-how many miles on the engine? I assume you were spraying meth when it happened?

 

Sorry to hear the bad news. Good luck on the rebuild.

 

I don't think that the block is salvageable, the sleeves will take care of the inside liner damage but not the outside edge damage.

I don't think the coupler would have contributed to the issue, it could be a detonation issue weakening the sleeve and breaking it off eventually or just an open deck not taking the high hp

Good luck with rebuild

 

Hey on the bright side that piston held up pretty well considering the violent event that obviously transpired immediately adjacent to it. I think it looks like a cylinder wall hot spot due to vapor as you mentioned. What coolant were you running? If you were running Evans NPG+ then I don't know what to say cause that's not suppose to happen.

Sorry to hear about this misfortune

 

Pistons are fine, no signs of detonation at all, other than possibly the dead cyl as a result of the failure. I am replacing the rings since the gaps were a little larger that I would have liked, due to my own error while assembling the engine the first time.

I may have just pushed the limits of the stock block! I put ruffely 9,000 miles on the car since the rebuild and 4,000 of those were with methanol. I drove the car daily and when I did have the chance to lay into it I alway ran it at high boost.

 

It is repairable, just not sure if the cost is worth it. My machinist is looking at it right now and looks like in order to fix this block they will have to bore the stock liner out, repair the allum (inner and outer jackets) by TIG welding it, deck it, bore it again, then install the new liner. Then they need to do the normal process to that cyl to get it ready for reassembly.

The cost of doing that is not much less than starting with a new core...

 

I can't tell from the pics, what cylinder was that? I have seen a lot of cars blow #3 cylinder including mine. Though yours is the first I have seen take out the cylinder wall.

There are a lot of us on built motor part deux, so don't feel too bad about it Still sucks though

 

i am truely sorry about what happened here. I cant wait to see your car back on the road you made some crazy numbers with ur TT kit and meth.

 

That was #4, driver side of the engine... What happened to yours when it let go? Was it just the head gasket? The inner part of the gasket on mine was torched, but the outter was still in one piece, pretty much untouched by the damage...

 

Mine was cylinder 3. I think I was just running too much boost (17-18 psi on the standard APS TT setup), especially for the regular ARP head studs and oem gaskets (all that was available at the time of my build). My head gaskets looked to be compromised on both #3 and #4 cylinders on on the outside. Basically no sign of detonation, just two broken ringlands on the #3 piston, which I guess in itself is a sign of detonation, but all other pistons seemed fine. They were standard duty Arias pistons.

 

I know you'll figure things out and get her back on the road again. Let me know if you need an extra set of hands on the weekend, I'll gladly come up and help you out.

 

Ouch Joe, let me know if there is anything I might be able to help you out with.

 

You mean the power limits? I was under the impression that Louie's was making around 50hp more with no issues so far, and even in road race conditions with no water/meth.

Either way, it sucks to see something like this happen. Best of luck getting the car back up and running.

 

Just speculation at this point, but this block may have just been weaker than others... Kind of the same theory as to why some stock engines make more power than others before they let go...

One thing is for sure, you can bet when it is back on the road it will be nastier than before! Got to have something good come out of this right? lol

 

Well i must say that the ride was badass before that happened!

One thing i was thinking after it happened was maybe something bad happened when the VDC was on during the first pull, I dont really know if that would cause that because of the fuel cut, something to think about.

 

Hey Joe, I like your positive outlook on things. Your engin/car was amazing, and no doubt she'll be even better very shortly.

It does literally, look like the aluminum outer wall just melted away. I will call you again tomorrow, because I want to run a couple of ideas by you.

 

what's a 'safe' egt temp, and at what point would detonation be be apparent on egt? sorry bout the car, atleast you have the skills to rebuild it so it won't be too bad. sucks none the less but it will come back stronger than before